Hey, guys. I'm having a weird problem with both my 50's classic strat, and my standard tele. When I play in a band setting, the piano and vocals are coming through my amp (a Fender Blues Junior). I really only notice it when using overdrive from the amp or my Blues Driver pedal, but then it's really noticable. I first noticed it on the strat, and thought the pickups were microphonic, so, I switched them out for Custom Shop '54 pickups. But, it still happens with the '54 pickups; I haven't had the chance to change pickups on the Standard Tele. But, since it's still doing it with the custom shop pickups, I'm not sure what's really going on. Only happens with the volume up on the guitars. When the volume is turned down on both guitars, the vocals and piano go away. I haven't noticed it on my Epiphone's yet, but I'll take them to band practice next week and see if they do it too.

Here are my thoughts, and I'd love to hear anyone else's thoughts on this. The pickup screws aren't a correct fit for the replacement pickguard on the strat. Maybe the sound from the P.A. is somehow making the pickup screws vibrate sending sound through the pickups? I also set my pickups pretty low, maybe the rubber tubing isn't making full contact with both the pickups and the pickguard, allowing the pickups to vibrate on both guitars? If a preamp tube was microphonic, would the 'microphonic sounds' go away when I turn down my guitar volume?
Thanks for all your help guys, Donnie.

Sounds like the tubes in the amp to me. Is this in a combo amp or a head.? Could be you need to use something like a tube damper.

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I've never heard of anything like this before..... so IM curious about what is the reason why that is happening

I once had a guitar that you could talk into and hear yourself on the amp especially with distortion on. Maybe you are too close to the other's set-up (or they are too close to you). It could be the tubes of the amp as well. Put some space between you and them, see if that works.

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RK

2007 Fender Highway 1
2012 American Deluxe
2015 MIM Dave Murray HHH
2010 Fender Blacktop
1987 Fender Avalon Acoustic
2012 Marshall DSL 15 watt head

Hi dalegribble (great username!):

That it is occuring with two different types of guitar shows that is not where the problem lies. And I presume you have tried playing with any effects units removed from the chain to be sure it's not one of them either? Interference via the mains power supply? Seems unlikely.

Then it must be the amp. You could check it by switching in the bass player's amp to your rig temporarily (it'll sound a bit odd but do no harm). Problem gone? Your amp's where the fault is.

The word "microphonic" is kinda tricky. Here's some useful pages about tubes (known as "valves" outside North America) at Marshall's website:

http://www.marshallamps.com/resources/s ... cement.asp

And here's how to test for microphonic tubes:

http://www.ehow.com/how_2043383_-locate ... ifier.html

However: a SERIOUS word of warning. Even when your amp is switched off there can be electrical charges stored inside which are potentially big enough to kill you. If you are not sure what you are doing with amp innards take it to a professional. Don't mess with your life.

I'll do anything you like with guitars, but when it comes to the insides of my amps I leave it all to a good tech...

Cheers - C

Thanks for your help guys. I've moved the amp around stage, but everything still comes through. I even tried hiding it behind an unused 4x12 bass cabinet, but vocals and keyboard still come through. I'll take the amp in to my local Fender dealer. The amp is pretty new, so I think I might be within the 90 day tube warranty. The problem is with recreating the problem so that they can see I'm not crazy. We have some pretty fierce stage volumes going on, and I only notice it at practice or when playing live with the band. I haven't noticed it at home, ever.
Before, I was playing through a decent peavey amp, and never noticed the tele feeding the vocals and keyboard to my amp, but the strat and the Blues Junior combo are new to my rig. Thanks again for your help. Donnie.

Hi again: don't worry about that. If the tubes are at fault a proper tech can tell even without recreating stage volume conditions.

And if it's not the tubes - well, you need his help in tracking down whatever it is.

This issue is obviously a little unclear to at least some of us. Be grateful if you care to tell us about it when you have a solution...?

Thanks - C

PS Hey, just another thought. I can't remember how the reverb is set up inside a Blues Junior. But I presume you've tried playing with the verb switched off? Something's nagging at the back of my mind about that...

Snap. I didn't even think about the reverb. You might have something there. I'll ask about it when I take it in. Ceri, you my friend may be a genius. I normally run the Master volume on 12, and adjust the preamp until I get the volume I need: usually around 3 or 3 1/2. I read somewhere that the reverb is tied into the master volume, so that might be it. I'll be sure to post what they told me.

Haha - truly not! Just a reader of guitar magazine Q&As...

Excellent - thank you!

Cheers - C

[Later] Well this is really bugging me now. The more I think about it the more I am convinced I have read someone talking about just this issue with a Blues Junior in a guitar magazine. It must have been in Guitarist and I even have a notion it was Simon Law writing - but I have spent a (happy) hour going back through many issues and I can't find it.

However. IF memory serves then they were dealing with a problem with the "short-tray spring reverb" in a Blues Junior causing unwanted noise - interference or microphone effects I'm not sure. They switched out the unit for a new one, but still had a problem.

Again, IF I'm recalling it right it came down to the exact position of the reverb unit within the amp. I don't know that amp's insides at all, but apparently there is some degree of play in the way the verb is seated in there. ...? Presumably this affects projection of unwanted sound transmissions into the circuitry... I feel there was some discussion of how the modern units are built, compared with how they were constructed back in a mythical "golden era" (yeah, yeah).

Something to discuss with a qualified tech, anyhow.

Be so much more useful if I could put my finger on that article... Dang! Well, I tried...

Cheers - C

Ok, it's officially an amp problem and not a guitar problem. I took it to my local Fender Authorized Service Center, and the guitar tech guy told me he thought the amp "Has some serious issues." He plugged in the amp with no guitar going into it, and it started making some pretty loud static and crackle noises. He asked me about that since I hadn't mentioned it, and I had to tell him it hadn't done that before.
So, it's in for service, and hopefully I'll get it back soon. Before the loud crackle and popping, the guitar tech thought it might be a microphonic tube, but he's changed his mind. I also mentioned that someone suggested the reverb might be the culprit, and he said he'd talk to the amp tech about it. So, that's my update. I appreciate everyone's help, and I'll post what the outcome is so that if someone else has this problem we'll all know what the problem might be. Thanks, Donnie.

The mid 90's MIA Blues juniors are terrible amps. The reverb on mine is stupidly weak its more of a noise circuit than a reverb circuit. My money is on the problem being there if its a old amp (the new MIM ones are much better). Also it could be something to do with the power amp stage, the amps have a really hot fixed bias that eats valves. Aside from those two rough guesses i've got no further clue. Amps really are a job for a bloke in a shop who takes em apart all day long.

Let us know what happens please.

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No no and no

Hello, Since the bass doesen't cause it, does the keyboards go thru the pa system too? Have you tried standing in the complete opposite direction of all PA speakers and monitors, or even turn them around just to make sure your guitar isn't picking them up. You said it was loud, and you said it was worse when your guitar was beefed up. Just a shot, ya never know, good luck!

Dalegribble,
I've got a Blues Jr I use some time but never had that problem. However I do recall a post earlier last year where a a young lady had a similar problem and ended up taking it back for some rehab. Try searching the amp forum first I think thats where she posted.

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I'm not slow... and I'm not fast... just sort of halffast...

Thanks for you input. As a little update...well, nothing has changed. I dropped the amp off Tuesday for my local Fender Service Center amp tech to check out the BJ, and that's the last I've got. I'm going to drop by the store today and see if it has made its way to the inspection table, and hopefully to see when I'll get it back. If anything changes, I'll be sure to let you guys know. Thanks, Donnie.